The lawn mowing industry is already aware of hydraulic systems for powering lawn mowers for use in their normal operation of cutting the grass. For example, U.S. Pat. No. 3,563,012 shows the use of a hydraulic motor incorporated in a hydraulic system which has reel type mowers supported on a tractor, and the hydraulic motors power the reels in the course of mowing the grass. Also, U.S. Pat. No. 3,744,522 discloses a hydraulic valve which has multiple settings for directing hydraulic fluid to various motors for operating the motors for any useful purpose. Of course the prior art already contains many other arrangements and embodiments of hydraulic systems for performing useful work, and wherein hydraulic motors are included in the system and are driven in forward and reverse directions, all under the control of hydraulic valves, such as spool type valves.
Still further, the lawn mower industry is also aware of arrangements for powering reels of reel type mowers such that the reel is powered in a forward grass-cutting direction and it can also be powered in a reverse direction for the purpose of sharpening the reel against the bed-knife. An example of one such prior art patent is U.S. Pat. No. 3,668,844 which shows a mechanically operated system for reversing the direction of rotation of the lawn mower reel for the sharpening and lapping purpose.
The present invention provides a hydraulic system for powering the lawn mower reel in both the forward and reverse directions, for the purposes mentioned. Accordingly, it is a general object and an advantage in the present invention to improve upon the prior art arrangements. In accomplishing this objective, the present invention utilizes a hydraulic system with a minimum of elements and components and with the components being relatively simple in their construction and arrangement in the system, all for providing a low-cost system which is also efficient and reliable.
A specific objective of the present invention is to provide a hydraulic system for powering a lawn mower wherein the mower reel can be powered in a reverse direction, for the purpose of lapping the reel against the mower bed-knife, and the reel is rotated at a limited speed such that, in the instance of backlapping, the lapping compound is not thrown off the reel blades, the system is not subjected to undue hydraulic pressure and the blades are not unduly heated by excessive rotational speeds. Also, the present invention provides a means for readily and easily reversing the direction of rotation of the mower reel, for the purpose of releasing foreign objects and debris which might be jamming the reel against the mower bed-knife.
Still further, the present invention provides a hydraulic system for powering a lawn mower and at least some of the components of the system are incorporated in a single housing, such that the hydraulic motor, and the hydraulic valve, and hydraulic-pressure relief valves can all be incorporated in a single housing which can be located adjacent the mower itself. With this compact arrangement, the components mentioned are all conveniently located and can therefore operate efficiently. Also, in this arrangement, the hydraulic passageway for the drainage of hydraulic fluid which might pass the seals of say the motor itself can be directed through an internal drain in the housing so that an external drain line or hose need not be provided and high-pressure seals need not be employed.
Still a further objective and advantage of the present invention is to provide a hydraulic system for a lawn mower wherein the system includes relief valve components and a control valve, all arranged so that the mower can be driven in a reverse direction and with the hydraulic pressure being less in the reverse direction than that of the forward direction of mower driving, and thus the reverse direction speed and development of heat and wear factors are controlled.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.